High flow nozzle system for flow control in bladder surge tanks

ABSTRACT

A surge tank is sized to retain a volume of fluid. A fluid inlet/outlet port is attached to the tank, and an elastomeric bladder is disposed within the tank and separates the fluid from a volume of gas. A nozzle system is disposed within the tank and has a nozzle member comprising a first plurality of axially elongate perforations, and a second plurality of perforations. The nozzle member can extend a partial or complete distance with tank. The tank body includes a throat that extends outwardly from a portion of the tank adjacent the port, and a portion of the nozzle member comprising the first plurality of perforations is disposed within the throat. An annular space exists adjacent the nozzle member in the neck to facilitate the flow of solid constituent within the fluid from the tank and into the nozzle member.

FIELD OF THE INVENTION

The present invention relates to surge tanks, and more specifically,bladder surge tanks having a nozzle system that is specially adapted tofacilitate the passage of a fluid system comprising a liquid and solidmixture to uniformly enter and exit the bladder surge tank.

BACKGROUND OF THE INVENTION

Surge tanks are designed to control pressure surges or transients inpipelines, which are created when the flow of the fluid is abruptlychanged. Pressure transients can be either positive or negative and arepotentially destructive and may result in damage to piping, pumps,instruments, fittings, or other system components.

Surge tanks have been used for years as a means for controlling pressuretransients. Some surge tanks employ a bladder design and are well knownhaving applications within various industries, including fire protectionsystems, municipal water and sewage systems, desalination facilities,fuel systems, and chemical and petrochemical facilities.

During a pump start up, for example, a high transient of pressure iscreated at the pump discharge. Installation of a bladder surge tank atthe pump discharge absorbs the fluid from the pump until the fluidachieves steady state velocity, then the surge tank discharges the fluidinto the system to balance the pressure and eliminate the pressuretransient. Pressure transients may also be created where there is asudden and abrupt cessation of liquid flow, hereto, bladder surge tankscan eliminate the pressure transient. Bladder surge tanks also haveapplication as a deluge surge tank where the instantaneous discharge offluid is required in, for example, fire protection systems.

Regardless of the application, the shape of the bladder during gasprecharge or fluid discharge is not totally controllable. In systemswhere the flow rate exceeds 500 gpm, the bladder may actually seal thetank's fluid inlet/outlet opening during liquid discharge and preventthe tank from emptying its liquid contents. To prevent this, somebladder surge tank manufacturers have placed a wire screen in the tank'sinlet/outlet opening. Unfortunately, such a screen actually impedes theliquid flow and is not totally effective in preventing the bladder fromblocking the tank's fluid inlet/outlet opening during fluid discharge.

Where there is a sudden flow of fluid into a bladder surge tank, theforce of the incoming fluid is concentrated and assumes the shape of thetank's fluid inlet/outlet opening. Such a column of fluid and itsassociated force is directed towards that portion of the bladderdirectly above the tank's inlet/outlet opening and can cause damage tothe bladder.

There remains a need for a bladder surge tank that eliminates thelikelihood of having the bladder block the tank's inlet/outlet openingduring fluid discharge and thus interfere with the flow of fluid out ofthe bladder surge tank. There also remains a need for a bladder surgetank that can redirect the fluid entering the bladder surge tank in amore uniform pattern, thus reducing the possibility of bladder damagefrom the force of the incoming fluid.

Further, in applications where the system fluid being handled is sewage,e.g., comprising a mixture of liquid and solid components, there is aneed to provide a bladder surge tank that can provide the desired degreeof surge protection without plugging or fouling, which would impair theability to provide surge protection, and which would require frequentmaintenance to ensure proper operation.

SUMMARY OF THE INVENTION

Surge tanks of this invention are specially engineered to provide adesired degree of surge protection for fluid systems comprising bothliquid and solid constituents. In an example embodiment, such surgetanks include a tank body having an interior wall adapted to retain avolume of fluid therein, e.g., a fluid comprising both liquid and solidconstituents. The tank body includes a fluid inlet/outlet port adjoinedthereto to facilitate the passage of fluid into and out of the tankbody. An elastomeric bladder is disposed within the tank body and isadapted to separate a volume of fluid within the tank from a volume ofgas within the tank. In an example embodiment, the tank body is chargedwith a precharge pressure of gas that resides between an inside wallsurface of the tank body and an adjacent surface of the bladder.

A nozzle system is disposed within the tank body, and is configuredhaving a nozzle member. The nozzle member comprises a first plurality ofperforations that extend a predetermined axial length along the nozzlemember. In an example embodiment, the first plurality of perforationsextend from an open end of the nozzle member that is positioned adjacentto the fluid inlet/outlet port. The first plurality of perforations havean axially elongate configuration. The nozzle member includes a secondplurality of perforations that extends an axial distance from the firstplurality of perforations.

Surge tanks of this invention can be oriented horizontally orvertically. The nozzle member can extend within the partial distance, orcompletely within the tank to an opposite tank interior wall surface. Inthe event that the nozzle member extends only a partial distance, theend opposite the open end is closed. In the event that the nozzle memberextends a complete distance, the end opposite the open end is open andis attached to a flanged member of the tank body. In an exampleembodiment where the nozzle member extend a complete distance within thetank body, the tank includes a clear-out opening that extends throughthe tank and that is in communication with an inside diameter of thenozzle member.

The tank body include a throat that extends outwardly from a bottomportion of the tank. At least a portion of the nozzle member comprisingthe first plurality of perforations is disposed within the throat. Thebladder includes a neck that is disposed within the throat and that isinterposed between an inside wall surface of the throat and the nozzlemember. In an example embodiment, the throat, bladder neck, and nozzlemember are sized to provide an annular space between the bladder and thenozzle member that is sufficient to facilitate the flow of solidconstituent matter within the fluid from the tank and into the nozzlemember. In an example embodiment, the first plurality of perforationsare sized to accommodate the passage of the solid constituent matterwithin the fluid therethrough.

Surge tanks constructed in this manner provide a desired degree of surgeprotection to fluid systems comprising a mixture of solid and liquidconstituents, and do so without unwanted plugging or fouling, therebyavoiding the need for frequent service or maintenance to ensure properoperation.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will bebetter understood by reference to the following detailed descriptionwhen considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a cross-sectional side elevation of a first embodimenthorizontal surge tank comprising a high flow nozzle system of thisinvention;

FIG. 2 is a sectional enlarged schematic view illustrating the high flownozzle system of FIG. 1;

FIG. 3 is a cross-sectional side view of the high flow nozzle systemtaken from a section of FIG. 2;

FIG. 4 is a cross-sectional side elevation of a second embodimenthorizontal surge tank comprising a high flow nozzle system of thisinvention;

FIG. 5 is a cross-sectional side elevation of a vertical surge tankcomprising a high flow nozzle system of this invention;

FIG. 6 is a sectional enlarged schematic view illustrating the high flownozzle system of FIG. 5; and

FIG. 7 is a cross-sectional side view of the high flow nozzle systemtaken from a section of FIG. 6.

DETAILED DESCRIPTION

In accordance with the present invention, there is provided improvedbladder surge tanks comprising high flow nozzle systems suitable for usein various types of fluid and or fluid/solid systems. In particular,bladder surge tanks comprising high flow nozzle systems of thisinvention are especially well suited for use in fluid systems such assewage systems that contain fluid and solid components.

FIG. 1 illustrates a first embodiment horizontal bladder surge tank 10comprising a high flow nozzle system 12 of this invention. Thehorizontal bladder surge tank 10 is a pressure vessel which contains abladder 14 disposed therein, a fluid inlet/outlet port 16, and thenozzle system 12 positioned within the tank adjacent the inlet/outletport 16. The horizontal bladder surge tank 10 comprises a body 18 havinga bladder access opening 20 disposed therethrough at one end of the tank10. Opposite the bladder access opening 20, the body can include a gascharging valve, a rupture disc, and a pressure gauge (not shown) Othercomponents of the surge tank may be added or deleted depending upon theparticular end use and related need.

Horizontal surge tanks can vary in size from about 250 gallons to morethan 5,000 gallons or more. Surge tanks used with high flow nozzlesystems of this invention may be constructed from a variety ofmaterials, so long as the material has sufficient strength to supportthe load and operating pressures and is chemically resistant to thefluid being pumped. In the preferred embodiment, the material ofconstruction is epoxy-coated carbon steel or stainless steel.

The horizontal bladder surge tank 10 is shown supported two or moresaddles 22. The bladder surge tank 10 may also be fitted with lift tabsif desired, which can allow the tank to be suspended and placed at thedesired location with ease.

The bladder 14 is located within and positioned adjacent at least apartial portion of an interior wall of the surge tank body 18. Thebladder 14 may be constructed from a variety of materials that aresuitable to contain gas under pressure as well as being resistant toattack from the fluid or liquid and/or solid contents within the system.The bladder 14 must also be strong enough to withstand the pressure orforce exerted upon it by the incoming fluid. In the preferredembodiment, the bladder 14 is made of a synthetic nitrile rubber, suchas buna-n.

The fluid inlet/outlet opening 16 is located along a bottom portion 24of the tank body 18, and allows fluid to enter and exit the tank 10. Thedimensions of the fluid inlet/outlet opening can vary depending upon theend use application and system needs.

The high flow nozzle system 12 of this invention includes a nozzlemember 26 that extends vertically a distance within the tank from aflanged terminal 28 that projects downwardly a distance from the bottomportion 24 of the tank body 18. The flanged terminal 28 is configured tofacilitate attachment with a flanged portion 30 of the fluidinlet/outlet port 16 by conventional attachment means, e.g., by boltedconnection or the like.

In this example embodiment, the nozzle member 26 includes a body havinga generally cylindrical cross section, is column shaped, that is open atone axial member end 31 positioned adjacent that fluid inlet/outlet port16, and that is closed at an opposite axial member end 32 positioneddistant the fluid inlet/outlet port 16. As illustrated in FIG. 1, inthis particular embodiment, the nozzle member is sized to project adesired partial distance vertically into the tank 10.

In an example embodiment, the length of the nozzle member is sized suchas to provide a desired inlet and outlet flow characteristic within thetank 10. Additionally, it is generally desired that the nozzle member besized such that it does not interfere with the desired operation ormovement of the bladder 14 within the tank 10. In a preferredembodiment, the nozzle member 26 extends vertically within the tank adistance that is less than about ½ of the tank diameter.

As illustrated in FIGS. 1 and 2, in an example embodiment, the nozzlemember 26 closed end 32 is rounded so that it does not otherwise snag ortear the bladder should the bladder come into contact with the nozzlemember during operation. The nozzle member 26 also includes a pluralityof perforations or openings 33 disposed through the body. The openings33 are positioned around the circumference of the nozzle member 26 atpredetermined locations, and extend axially therealong a desired axiallength of the nozzle member. In a preferred embodiment, the openings arepositioned lengthwise along the portion of the nozzle member extendingvertically from the tank bottom portion 24.

The perforations 33 are positioned along the wall surface of the nozzlemember 26 to disperse the incoming liquid uniformly over a wide area soas to minimize any damage to the bladder that could occur were the forceof the incoming liquid focused upon one area of the bladder. The totalarea of the perforations 33 preferably exceeds the total area of thetank's fluid inlet/outlet port 16. The size, number and location ofperforations 33 are determined by a series of mathematical calculationsbetter described below. The size of the perforations 33 will also varydepending upon the operating pressure of the system.

Referring to FIGS. 1 to 3, the nozzle member 26 also includes one ormore elongate openings or perforations 34 that are positioned verticallybelow the plurality of perforations 33. In an example embodiment, theelongate perforations 34 are oriented along the nozzle member in amanner that extends axially along a length of the nozzle member 26. Theelongate openings 34 are disposed through a portion of the nozzle memberthat is positioned within a cylindrical throat 36 of the tank thatextends downwardly from the tank bottom portion 24. The cylindricalthroat 36 is sized and configured to accommodate placement of a desiredsection of the nozzle member 26 therein. The cylindrical throat includesan open end that is positioned adjacent the nozzle member open end 31,and that is connected to the flanged terminal 28.

In an example embodiment, the cylindrical throat 36 has an insidediameter that is greater than that of the nozzle member outsidediameter, and that is sized to provide a desired tolerance between awall section of the bladder 14 that is positioned adjacent thecylindrical throat sidewall surface and the nozzle member. Ideally, thetolerance is sufficient to facilitate the flow and drainage of fluid andany solid matter 38 disposed within the tank, e.g., when the tank isplaced into a sewage system application, from the tank and through thenozzle member via the elongate perforations 34 (as indicated by thearrows in FIGS. 2 and 3). In an example embodiment, it is desired that atolerance in the range of from about 5 cm to 15 cm be provided for usein a sewage system application. In a sewage system application, it isdesired that the tolerance be such as to permit the passage of solidshaving a size of about 2.54 cm to pass thereby.

Additionally, it is desired that the cylindrical throat 36 be sizedaxially to accommodate therein a majority of the nozzle member lengthcontaining the elongate slotted perforations 34. Functionally, this isdesired to facilitate the free flow and drainage of any solid mattercontained within the fluid from the body. In an example embodiment, itmay be desired that at least about 50 percent, and preferably greaterthan about 75 percent, of the slotted elongate opening length bedisposed within the cylindrical throat.

The number of the slotted elongate openings disposed through the nozzlemember, the axial length of the slotted elongate openings, and the widthof the slotted elongate openings are understand to vary depending on theparticular end use application. In an example embodiment, where thesurge tank is placed in a sewage system application, it is desired thatthe number, length and width of the slotted elongations be sufficient tofacilitate the passage the solid matter entrained with the sewage fluidthrough the nozzle member 26 without plugging and/or otherwise causingan unwanted pressure drop through he nozzle member.

In an example embodiment, the nozzle member slotted elongate openings 34are positioned circumferentially therearound and equidistant from oneanother. In such example, the nozzle member may comprise in the range offrom about 2 to 20 slotted elongate openings, and the slotted elongateopenings can have an axial length in the range of from about 5 to 10 cm,and each have a width that is in the range of from about 3 to 5 cm. Itis to be understood that the above provided dimensions arerepresentative of a single example embodiment, and that otherembodiments within the scope of this invention may have slotted elongateopening dimensions that are different from those representativedimensions provided above.

As noted above, the bladder 14 is disposed within the tank 18. Thebladder, as used in this horizontal embodiment illustrated in FIGS. 1 to3, includes a cylindrical neck that is positioned within the cylindricalthroat 36 with its wall surface adjacent a wall surface of thecylindrical throat 36. In an example embodiment, the bladder neck isreinforced to ensure that it does not collapse towards the slottedelongate openings during operation. The bladder neck includes a flaredend 39 (as best shown in FIG. 1) that is interposed between the flanges28 and 30, and thereby operates to both fix the bladder into placewithin the throat, and operates to seal the bladder within the tank.

Configured in this manner, the flared end 39 of the bladder neckoperates to retain the collar in place within the tank cylindricalthroat 36 so that the bladder does not collapse or move inwardly towardthe nozzle member when the pressure within the bladder causes the fluid,e.g., liquid and/or solid matter, to flow from the tank and through thenozzle member. This ensures that such desired fluid flow is notobstructed by the bladder, and that the bladder is not extruded throughthe elongate openings in the nozzle member.

FIG. 4 illustrates a second embodiment horizontal surge tank 40comprising a high flow nozzle system 42 of this invention. Thehorizontal bladder surge tank 40 is a pressure vessel that contains abladder 44 disposed therein, a fluid inlet/outlet port 46, and thenozzle system 42 positioned within the tank adjacent the inlet/outletport 46. The horizontal bladder surge tank 40 comprises a body 48 havinga bladder access opening 50 disposed therethrough at one or more ends ofthe tank 40. The body 48 can include a gas charging valve, a rupturedisc, and a pressure gauge (not shown) Other components of the surgetank may be added or deleted depending upon the particular end use andrelated need.

Like the first embodiment horizontal surge tank illustrated in FIG. 1,the fluid inlet/outlet opening 46 is located along a bottom portion 52of the tank body 48, and allows fluid to enter and exit the tank 40. Thedimensions of the fluid inlet/outlet opening 46 can vary depending uponthe end use application and system needs.

The high flow nozzle system 42 of this invention embodiment includes anozzle member 54 that extends vertically a distance within the tank froma flanged terminal 56, that projects downwardly a distance from thebottom portion 52 of the tank body 48. The flanged terminal 56 isconfigured to facilitate attachment with a flanged portion 58 of thefluid inlet/outlet port 46 by conventional attachment means, e.g., bybolted connection or the like.

In this second embodiment, the nozzle member 54 includes a body having agenerally cylindrical cross section, is column shaped, that is open atone axial member end 60 positioned adjacent the fluid inlet/outlet port46, and that has an opposite axial 62 that is positioned adjacent aclear-out opening 64 that extends a distance away from a top portion 66of the tank body 48. As illustrated in FIG. 4, unlike the firstembodiment nozzle member that extended only a partial vertical distancewithin the tank, in this second embodiment the nozzle member 54 is sizedto project a complete vertical distance within the tank from the tankbottom portion 52 to the tank top portion 66.

The nozzle member 54 includes a plurality of perforations or openings 68disposed through the body. The openings 68 are positioned around thecircumference of the nozzle member 54 at predetermined locations, andextend axially therealong a desired axial length of the nozzle member.In a preferred embodiment, the openings 68 are positioned lengthwisealong the portion of the nozzle member extending vertically from thetank bottom portion 52 to the tank upper portion 66.

The perforations 68 are positioned along the wall surface of the nozzlemember 54 to disperse the incoming liquid uniformly over a wide area soas to minimize any damage to the bladder that could occur were the forceof the incoming liquid focused upon one area of the bladder. The totalarea of the perforations 68 preferably exceeds the total area of thetank's fluid inlet/outlet port 46. The size, number and location ofperforations 68 are determined by a series of mathematical calculationsbetter described below. The size of the perforations 68 will also varydepending upon the operating pressure of the system.

Like the first embodiment disclosed above and illustrated in FIGS. 1 to3, the second embodiment nozzle member 54 also includes one or moreelongate openings or perforations 70 that are positioned verticallybelow the plurality of perforations 68, that are provided in the samemanner and for the purpose as disclosed above for the first embodiment.The elongate openings 70 are disposed through a portion of the nozzlemember positioned within a cylindrical throat 72 of the tank thatextends downwardly from the tank bottom 52, and that is sized andconfigured to accommodate placement of a desired section of the nozzlemember 54 therein. The cylindrical throat includes an open end that ispositioned adjacent the nozzle member open end 60, and that is connectedto the flanged terminal 56.

In such second invention embodiment, the cylindrical throat and nozzlemember are sized and configured as disclosed above for the firstembodiment, to provide a desired tolerance therebetween to facilitate adesired flow and drainage of fluid and any solid matter disposed withinthe tank, e.g., when the tank is placed into a sewage systemapplication, from the tank and through the nozzle member via theelongate perforations 70. The number of the slotted elongate openingsdisposed through the nozzle member, the axial length of the slottedelongate openings, and the width of the slotted elongate openings areunderstand to vary depending on the particular end use application.

The bladder 44 includes a cylindrical neck that is disposed within thetank cylindrical throat 72 in the same manner as described above for thefirst invention embodiment. The bladder neck includes a flared endinterposed between the flanges 56 and 58 to secure the bladder intoplace and seal the bladder within the tank.

In this second invention embodiment, the nozzle member 54 extendsvertically the entire diameter of the tank, thereby providing a largerflow area within the tank and providing a second connection point withinthe tank. The nozzle member end 62 is disposed within a cylindricalthroat 74 that extends from the tank upper portion 66 to the clear-outopening 64. The bladder 44 includes a neck that is disposed within thecylindrical throat, and further includes a flared end that is interposedbetween flanged ends 76 and 78 of the cylindrical throat and a blindflange connected thereto.

The clear-out opening 64 is provided to enable a user to open the tank,by removing the blind flange 78, and cleaning or clearing out the nozzlemember 54, e.g., by water flush or the like. In practice, should thebladder tank become clogged or otherwise restricted during use, theability to water flush the nozzle member 54 via such clear-out openingprovides an easy and efficient way of restoring the desired operation ofthe tank.

Bladders used in conjunction with the horizontal and/or vertical surgetanks of this invention are preferably precharged with a desiredpressure of air or gas. In a preferred embodiment, the bladders and thesurge tanks are configured such that the gas precharge exists between aportion of the surge tank inside wall surface and an outside surface ofthe bladder. The exact precharge pressure that is used in the surgetanks of this invention can and will vary on a number of differentfactors as well as the intended end use application.

FIG. 5 illustrates a vertical bladder surge tank 80 comprising a highflow nozzle system 82 of this invention. The vertical bladder surge tank80 is a pressure vessel which contains a bladder 84 disposed therein, afluid inlet/outlet port 86, and the nozzle system 82 positioned withinthe tank adjacent the inlet/outlet port 86. The vertical bladder surgetank 80 comprises a body 88 having a bladder access opening 90 disposedtherethrough at one end of the tank 80. The body includes a gas chargingvalve 92, a rupture disc 94, and a pressure gauge 96. Other componentsof the surge tank may be added or deleted depending upon the particularend use and related need. In an example embodiment and as noted above,the tank is configured so that a desired precharge pressure is imposedbetween the bladder and the inside wall of the tank, such that thebladder operates to isolate the fluid being handled within the tank sothat it is not placed into contact with the pressurized gas.

In the vertical surge tank of FIG. 5, gas is introduced into the tank'sinterior cavity by way of the gas charging valve 92. In a surge event,the bladder 84 is filled with the surge liquid, and typically thebladder 44 is filled to between about 80% to 85% capacity. In apreferred embodiment, the gas is nitrogen.

Vertical surge tanks can vary in size from about 250 gallons to morethan 5,000 gallons or more. Surge tanks used with high flow nozzlesystems of this invention may be constructed from a variety ofmaterials, so long as the material has sufficient strength to supportthe load and operating pressures and is chemically resistant to thefluid being pumped. In the preferred embodiment, the material ofconstruction is epoxy-coated carbon steel or stainless steel.

The vertical bladder surge tank 80 is shown supported by legs 98, onlytwo of which are shown. The bladder surge tank 80 may also be fittedwith lift tabs if desired, which can allow the tank to be suspended andplaced at the desired location with ease.

The bladder 84 is located within a surrounding interior wall of thesurge tank body 88, and can be constructed from the same types ofmaterials noted above for the horizontal surge tank embodiments. Thefluid inlet/outlet opening 86 is located along a bottom portion 100 ofthe tank body 88, and allows fluid to enter and exit the tank 80. Thedimensions and orientation of the fluid inlet/outlet 86 opening can varydepending upon the end use application and system needs. For example, inthe example embodiment illustrated in FIG. 5, the fluid inlet/outlet 86is configured having a right angle opening oriented to direct the flowof fluids entering or exiting the tank in perpendicular to the nozzlesystem 82. This orientation can and will vary depending on theparticular end use application.

The nozzle system 82 includes a nozzle member 102 that extendsvertically a distance within the tank from a flanged terminal 104 thatprojects downwardly a distance from the bottom portion 100 of the tankbody 88. The flanged terminal 104 is configured to facilitate attachmentwith a flanged portion 106 of the fluid inlet/outlet port 86 byconventional attachment means, e.g., by bolted connection or the like.

In this example embodiment, the nozzle member 102 includes a body havinga generally cylindrical cross section, is column shaped, that is open atone axial member end 108 positioned adjacent the fluid inlet/outlet port86. The nozzle member 102 includes an opposite axial end 110 that isalso open and that is positioned adjacent the bladder access opening 90.In this example embodiment, the nozzle member 102 is sized having aaxial length that extends within the vertical length of the tank, e.g.,from the bottom portion 100 to a tank upper portion 112. The nozzlemember is sized vertically and diametrically to provide a desired inletand outlet flow characteristic within the tank 80.

The nozzle member 102 includes a plurality of perforations or openings114 disposed through the body. The openings 114 are positioned aroundthe circumference of the nozzle member 102 at predetermined locations,and extend axially therealong a desired axial length of the nozzlemember. In a preferred embodiment, the openings are positionedlengthwise along a major length of the nozzle member extendingvertically from the tank bottom portion 100.

The perforations 114 are positioned along the wall surface of the nozzlemember 102 to disperse the incoming liquid uniformly over a wide area soas to minimize any damage to the bladder that could occur were the forceof the incoming liquid focused upon one area of the bladder. The totalarea of the perforations 114 preferably exceeds the total area of thetank's fluid inlet/outlet port 86. The size, number and location ofperforations 114 are determined by a series of mathematical calculationsbetter described below. The size of the perforations 114 will also varydepending upon the operating pressure of the system.

In this example embodiment, the nozzle member 102 is connected with thetank at both the tank top and tank bottom. The nozzle member 102 isconnected with the tank along the tank bottom portion 100 in the samemanner disclosed above for the horizontal tank embodiments; namely, theportion of the nozzle member adjacent open end 108 is concentricallypositioned within a cylindrical throat 116 of the tank.

The bladder 84 includes a neck that is positioned adjacent a wallsurface of the cylindrical throat, wherein the neck includes a flaredend that is interposed between the flanges 104 and 106 to secure thebladder into place. In a preferred embodiment, the neck is reinforced asnoted above to prevent the bladder from collapsing against the nozzlemember 102 during operation, thereby to avoid plugging the nozzle memberand/or being extruded into the nozzle member.

The nozzle member 102 is connected with the tank along the tank topportion 112 by placement of the nozzle member end 110 centered against aflanged member 118, wherein the flanged member 118 is attached to aflanged end 120 of the tank by conventional method such as by boltedattachment. The flanged member 118 includes a clear-out port 122 that isdisposed axially therethrough and that is positioned to be in fluid flowcommunication with an inside diameter of the nozzle member 102. In anexample embodiment, the clear-out port 122 projects outwardly and awayfrom the flanged member 118, and inwardly a desired length into theinside diameter of the nozzle member.

The flanged member 118 includes an access element 124 that is removablyattached to the clear-out port 122, and that is easily accessible from aposition outside of the tank. In an example embodiment, the accesselement 124 is connected by threaded communication with the flangedmember 118, and has an outside surface that is configured to facilitateremoval by use of a conventional tool, e.g., a wrench, socket or thelike. Once the access element 124 is removed, a suitable clearing devicecan be connected thereto by use of a complementary coupling.

The clearing device can be one that is designed to clear out the insidediameter of the nozzle member by mechanical, hydraulic, and/or pneumaticmeans. In an example embodiment, the clearing device is a fluid handlingmember configured to subject the inside diameter of the nozzle member toa pressurized water stream.

The bladder 84 comprises a neck that is configured for attached alongthe tank top portion 112. In an example embodiment, the tank top portion112 includes a cylindrical throat 126 that extends a desired lengthoutwardly therefrom. The bladder neck is positioned adjacent an insidewall surface of the cylindrical throat 126 and includes a flared endthat is interposed between the flanged end 120 and the flanged member118 to hold the bladder securely in place and to prevent unwantedleakage.

Referring to FIGS. 5 to 7, the nozzle member 102 also includes one ormore elongate openings or perforations 128 that are positionedvertically below the plurality of perforations 114. In an exampleembodiment, the elongate perforations 128 are oriented along the nozzlemember in a manner that extends axially along a desired length of thenozzle member 102. The elongate openings 128 are disposed through aportion of the nozzle member that is positioned within the cylindricalthroat 116 of the tank that extends downwardly from the tank bottomportion 100. As noted above, the cylindrical throat 116 is sized andconfigured to accommodate placement of a desired section of the nozzlemember 102 therein. The cylindrical throat 116 includes an open end thatis positioned adjacent the nozzle member open end 108, and that isconnected to the flanged terminal 104.

In an example embodiment, the cylindrical throat 116 has an insidediameter sized greater than that of the nozzle member outside diameterto provide a desired tolerance between a wall section of the bladder 84that is positioned adjacent the cylindrical throat sidewall surface andthe nozzle member. As noted above for the horizontal tank embodiment,the tolerance is sufficient to facilitate the flow and drainage of fluidand any solid matter 130 disposed within the tank, e.g., when the tankis placed into a sewage system application, from the tank and throughthe nozzle member via the elongate perforations 128 (as indicated by thearrows in FIGS. 6 and 7).

In an example embodiment, it is desired that a tolerance in the range offrom about 5 cm to 15 cm be provided for use in a sewage systemapplication. In a sewage system application, it is desired that thetolerance be such as to permit the passage of solids having a size ofabout 2.54 cm to pass thereby.

The cylindrical throat 116 is preferably sized axially to accommodatetherein a majority of the nozzle member length containing the slottedelongate perforations 114. Functionally, this is desired to facilitatethe free flow and drainage of any solid matter contained within thefluid from the body. In an example embodiment, it may be desired that atleast about 50 percent, and preferably greater than about 75 percent, ofthe slotted elongate opening length be disposed within the cylindricalthroat 116.

As with the horizontal tank embodiment disclosed above, the number ofslotted elongate openings disposed through the nozzle member, the axiallength of the slotted elongate openings, and the width of the slottedelongate openings for use in the vertical tank embodiment are understandto vary depending on the particular end use application. In an exampleembodiment, where the surge tank is placed in a sewage systemapplication, it is desired that the number, length and width of theslotted elongations be sufficient to facilitate the passage of the solidmatter entrained with the sewage fluid through the nozzle member 102without plugging and/or otherwise causing an unwanted pressure dropthrough the nozzle member.

In an example embodiment, the nozzle member slotted elongate openings128 are positioned circumferentially therearound and equidistant fromone another. In such example, the nozzle member may comprise in therange of from about 2 to 20 slotted elongate openings, and the slottedelongate openings can have an axial length in the range of from about 5to 10 cm, and each have a width that is in the range of from about 3 to5 cm. It is to be understood that the above provided dimensions arerepresentative of a single example embodiment, and that otherembodiments within the scope of this invention may have slotted elongateopening dimensions that are different from those representativedimensions provided above.

For both the horizontal and vertical surge tank embodiments, a series ofequations is used in calculating the number and placement of eachperforation in the nozzle system nozzle member. In an exampleembodiment, the following mathematical equations are used to calculatethe number and placement of perforations for use within a 500 gallonvertical surge tank having an 8-inch diameter fluid inlet/outlet openingat an operating pressure of 250 psi.

Surge Tank Nozzle System Mathematical Formulas

Three sections of holes

Nine rows in each section

Sixteen holes in each row

Number of holes in nozzle member=3 sections×9 rows×16 holes=432 holes

Approximate hole diameter=0.50 in.

Surface area of holes in nozzle member=432×(π/4)(0.50)²=84.8 in.².

Inlet/outlet nozzle system area (8 in. Sch 40 pipe)

ID=7.981 in.;(π/4)(7.981)²=50.0 in.²

The total surface area of the perforations in nozzle system nozzlemember for this particular example is approximately 84.8 square inches;and the total surface area of the tank's fluid inlet/outlet port isapproximately 50 square inches.

The above-described embodiments of the present invention are merelydescriptive of its principles and are not to be considered limiting. Thescope of the present invention instead shall be determined from thescope of the following claims including their equivalents.

1. A surge tank comprising: a tank body having an interior wall adaptedto retain a volume of fluid therein; a fluid inlet/outlet port adjoinedto the tank body to allow fluid to enter and exit the tank body; anelastomeric bladder positioned within the tank body and adapted toseparate a volume of fluid within the tank from a volume of gas; and anozzle system disposed within the tank body and including a nozzlemember comprising: a first plurality of perforations extending apredetermined axial length along the nozzle member from an open end ofthe nozzle member adjacent the fluid inlet/outlet port, wherein thefirst plurality of perforations have an axially elongate configuration;and a second plurality of perforations extending from the firstplurality of perforations a predetermined axial length along the nozzlemember.
 2. The surge tank as recited in claim 1 wherein the nozzlemember extends vertically a partial distance within the tank andincludes a closed end opposite the open end.
 3. The surge tank asrecited in claim 1 wherein the nozzle member extends vertically acomplete distance within the tank and includes an opposite end that isconnected with the tank.
 4. The surge tank as recited in claim 1 whereinthe tank includes a throat that extends outwardly from a tank bottomportion, and wherein at least a portion of the nozzle member comprisingthe first plurality of perforations is disposed within the throat. 5.The surge tank as recited in claim 4 wherein the bladder includes a neckthat is disposed within the throat and that is interposed between aninside wall surface of the throat and the nozzle member.
 6. The surgetank as recited in claim 5 wherein the throat, bladder neck, and nozzlemember are sized to provide an annular space between the bladder and thenozzle member that is sufficient to facilitate the flow of solid matterwithin the fluid from the tank and into the nozzle member.
 7. The surgetank as recited in claim 1 wherein the surge tank is a horizontalbladder surge tank.
 8. The surge tank as recited in claim 1 wherein thesurge tank is a vertical bladder surge tank.
 9. The surge tank asrecited in claim 1 further comprising a clear-out opening that extendsthrough a portion of the tank wall, and that is in communication with aninside diameter of the nozzle member.
 10. The surge tank as recited inclaim 1 wherein the fluid is a liquid and solid mixture, and wherein thefirst plurality of perforations are sized to accommodate the passage ofthe solid constituents therethrough.
 11. A horizontal bladder surge tankcomprising: a tank body having an interior wall adapted to retain avolume of fluid therein, the fluid comprising both liquid and solidconstituents; a fluid inlet/outlet port adjoined to a base portion ofthe tank body to facilitate the flow of fluid into and out of the tankbody; a bladder disposed horizontally within the tank body andpositioned adjacent to at least a portion of the tank interior wall, thebladder forming a barrier between the fluid and a gas within the tankbody; and a nozzle system disposed within the tank body and comprising anozzle member projecting radially inwardly a distance from the tank baseportion, the bladder being interposed between the nozzle member and theinterior wall, and the nozzle member extending from the fluidinlet/outlet port and comprising: a first plurality of elongate openingsdisposed therethrough and extending an axial distance along the nozzlemember from an open end positioned adjacent the fluid inlet/outletopening; and a second plurality of openings disposed therethrough andextending an axial distance along the nozzle member from the firstplurality of elongate openings to an end of the nozzle member oppositethe open end.
 12. The surge tank as recited in claim 11 wherein the tankincludes a throat that projects outwardly from the tank base portion andthat accommodates a portion of the nozzle member therein that comprisesthe first plurality of elongate openings.
 13. The surge tank as recitedin claim 12 wherein the bladder includes a neck that is disposed withinthe throat and that is interposed between the throat and the nozzlemember, wherein an annular space is formed between the bladder neck andthe nozzle that is of sufficient dimension to facilitate the passage ofthe solid constituents in the fluid therethrough.
 14. The surge tank asrecited in claim 12 wherein the elongate perforations have an axialdimension that extends along a majority of the axial dimension of thethroat.
 15. The surge tank as recited in claim 11 wherein the nozzlemember end opposite the open end is closed and is positioned a partialdistance within the tank, and wherein the second plurality ofperforations extend along a length of the nozzle member adjacent theclosed end.
 16. The surge tank as recited in claim 11 wherein the nozzlemember extends a complete distance within the tank, wherein the endopposite the open end is connected with the tank, and wherein the secondplurality of perforations extend along a length of the nozzle memberadjacent the opposite end.
 17. The surge tank as recited in claim 16wherein the end opposite the open end is open and connected with aflange member attached to the tank, and wherein the flange memberincludes means for accessing an inside diameter of the nozzle member forclearing the same of any obstructions.
 18. The surge tank as recited inclaim 11 wherein the first plurality of elongate perforations are sizedto facilitate passage of the solid constituents in the fluidtherethrough.
 19. A vertical bladder surge tank comprising: a tank bodyhaving an interior wall adapted to retain a volume of fluid comprisingliquid and solid constituents therein; a fluid inlet/outlet portadjoined to a base portion of the tank body that allows the fluid toenter and exit the tank body; a bladder disposed vertically within thetank body and connected with the interior wall, wherein the tank ischarged with a pressurized gas between the interior wall and thebladder, and wherein the bladder forms a barrier between fluid and gaswithin the tank body; and a nozzle system disposed within the tank bodyand comprising a nozzle member projecting axially inwardly a distancefrom a base portion of the tank, the bladder being interposed betweenthe nozzle member and the interior wall and the bladder, the nozzlemember extending from the fluid inlet/outlet port and comprising: afirst plurality of elongate openings disposed therethrough and extendingan axial distance along the nozzle member from an open end positionedadjacent the fluid inlet/outlet opening; and a second plurality ofopenings disposed therethrough and extending an axial distance along thenozzle member from the first plurality of elongate openings to an endopposite the open end.
 20. The surge tank as recited in claim 19 whereinthe tank includes a throat that projects outwardly from the tank baseportion and that accommodate a portion of the nozzle member therein thatcomprises the first plurality of elongate openings.
 21. The surge tankas recited in claim 20 wherein the bladder includes a neck that isdisposed within the throat and that is interposed between the throat andthe nozzle member, wherein an annular space is formed between thebladder neck and the nozzle that is of sufficient dimension tofacilitate the passage of a the solid constituents in the fluidtherethrough.
 22. The surge tank as recited in claim 20 wherein theelongate perforations have an axial dimension that extends along amajority of the axial dimension of the throat.
 23. The surge tank asrecited in claim 19 wherein the nozzle member extends a completedistance within the tank, wherein the end opposite the open end isconnected with the tank, and wherein the second plurality ofperforations extend along a length of the nozzle member adjacent theopposite end.
 24. The surge tank as recited in claim 23 wherein the endopposite the open end is open and connected with a flange memberattached to the tank, and wherein the flange member includes means foraccessing an inside diameter of the nozzle member for clearing the sameof any obstructions.
 25. The surge tank as recited in claim 19 whereinthe first plurality of elongate perforations are each sized tofacilitate passage of the solid constituents in the fluid therethrough.